A Manhattan social climber and self-proclaimed presidential historian charged with stealing millions of dollars worth of historic documents in Maryland also swiped documents from two venerable New York museums during his crime spree, according to the feds.

In March, limelight-loving Barry Landau, 63 — who’s hobnobbed with everyone from Queen Elizabeth to the Pope and the Clintons — ripped off the New-York Historical Society, making off with a letter penned in 1780 by Benjamin Franklin to American Revolution hero John Paul Jones, prosecutors claim.

Just three months earlier, Landau pilfered seven presidential speeches, signed and annotated by Roosevelt, from the Franklin D. Roosevelt Presidential Library and Museum in Hyde Park.

Landau spirited the documents back to his museum-like West 57th Street apartment, and later sold four of the Roosevelt letters to a private buyer for $35,000, according to prosecutors.

The alleged New-York Historical Society theft is particularly galling, a source told The Post, because Landau is a longtime friend of former Secretary of State Henry Kissinger and his wife, Nancy, who are patrons of the museum.

Landau was arrested last week on theft and conspiracy charges after he allegedly stole $6 million worth of artifacts from the Maryland Historical Society.

He was denied bail Monday by a Maryland judge. Prosecutors said an ongoing probe has turned up items from the National Archives, Vassar College, and the Connecticut Historical Society.

Landau’s assistant and alleged accomplice, Canadian Jason Savedoff, 24, are out on $250,000 bail.

Those familiar with the alleged scheme said Landau and Savedoff often sweet-talked their way into the archives and records rooms of various historical museums, showing up with cupcakes or cookies for the staff.

But during the alleged July 9 Maryland heist, a suspicious employee saw Savedoff take a document. A subsequent search of a locker the men had rented turned up 60 purportedly purloined items.